Dual functions for the ssDNA-binding protein RPA in meiotic recombination
Dual functions for the ssDNA-binding protein RPA in meiotic recombination
复制标题
单链 DNA 结合蛋白 RPA 在减数分裂重组中的双重功能
DOI：
10.1371/journal.pgen.1007952
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发表时间：
2019-02-01
期刊：
影响因子：
4.5
通讯作者：
Wang, P. Jeremy
中科院分区：
文献类型：
--
作者：
Shi, Baolu;Xue, Jiangyang;Wang, P. Jeremy
减数分裂重组允许同源染色体之间的遗传物质交换。复制蛋白A（RPA）复合物，主要的单链DNA结合复合物，是需要的几乎所有方面的DNA代谢，但它在哺乳动物减数分裂重组的作用仍然未知，由于RPA突变小鼠的胚胎致死性。RPA是RPA 1、RPA 2和RPA 3的异三聚体。我们发现，最大的亚基RPA 1的丢失导致RPA 2和RPA 3的消失，导致RPA复合物的缺失。使用一种可诱导的种系特异性失活策略，我们发现RPA的缺失完全消除了RAD 51/DMC 1重组酶对程序性减数分裂DNA双链断裂的加载，从而阻断了染色体配对和突触所需的链侵入。令人惊讶的是，MEIOB、SPATA 22和ATR对DNA双链断裂的加载是RPA非依赖性的，并且在不存在RPA的情况下不促进RAD 51/DMC 1募集。最后，RPA的失活减少了交叉形成。我们的研究结果表明，RPA在减数分裂重组中起着两个不同的作用：在重组酶的招聘在早期阶段和促进交叉形成在后期阶段的重要作用。
Meiotic recombination permits exchange of genetic material between homologous chromosomes. The replication protein A (RPA) complex, the predominant ssDNA-binding complex, is required for nearly all aspects of DNA metabolism, but its role in mammalian meiotic recombination remains unknown due to the embryonic lethality of RPA mutant mice. RPA is a heterotrimer of RPA1, RPA2, and RPA3. We find that loss of RPA1, the largest subunit, leads to disappearance of RPA2 and RPA3, resulting in the absence of the RPA complex. Using an inducible germline-specific inactivation strategy, we find that loss of RPA completely abrogates loading of RAD51/DMC1 recombinases to programmed meiotic DNA double strand breaks, thus blocking strand invasion required for chromosome pairing and synapsis. Surprisingly, loading of MEIOB, SPATA22, and ATR to DNA double strand breaks is RPA-independent and does not promote RAD51/DMC1 recruitment in the absence of RPA. Finally, inactivation of RPA reduces crossover formation. Our results demonstrate that RPA plays two distinct roles in meiotic recombination: an essential role in recombinase recruitment at early stages and an important role in promoting crossover formation at later stages.